This invention relates generally to baling machines typically referred to as "round balers" which form cylindrical roll bales of crop material.
In a conventional type of roll baling machine such as shown in U.S. Pat. No. 3,901,007, an upper apron moves from a starting position when the machine is empty to a final position during formation of a bale. This movement of the upper apron is controlled by a rotatable arm assembly which helps support the upper apron. Rotation of the arm assembly allows the inner course of the upper apron contacting the periphery of the roll bale to expand as the bale increases in diameter. This ensures that the arc of the bale periphery in contact with the upper apron will always be the same during bale formation. If the machine shown in the above-mentioned patent is modified so that a greater arc of the bale periphery is in contact with the upper apron, the total length of the upper apron would have to be increased. Therefore, the arms of the arm assembly would have to be made longer so that the longer upper apron would return to its proper starting position when the machine is empty. These longer arms for the arm assembly shown in the above-mentioned patent would be undesirable because they could result in a machine of excessive overall height or they could interfere with bale formation.